PubMed Health⌕ Search

Biomedical subjects

D J Carr

Publications and source records attributed to D J Carr.

106 records · Page 6Linked to original sources
PubMed1986

A comparative evaluation of three neonatal ventilators.

The comparative reliability of three neonatal ventilators was evaluated using an infant model lung to simulate airway resistance and lung compliance. The ventilators tested were the Bourns BP200, the Healthdyne TI-11, and a positive-pressure ventilator called the PREEMIE (not commercially manufactured) used in several neonatal units in the Milwaukee area. The Bourns and Healthdyne ventilators generated similar airway and alveolar pressures while the PREEMIE produced alveolar, peak inspiratory, and positive end-expiratory pressures that exceeded the respective ventilator pressure settings by up to 11 cm H2O. The simple method described here should be generally useful for the evaluation of neonatal ventilator output.

Airway Resistance↗
PubMed1986

Thrombotic thrombocytopenic purpura associated with metastatic gastric adenocarcinoma: successful management with plasmapheresis.

A patient with metastatic gastric adenocarcinoma had progressive microangiopathic red blood cell changes, thrombocytopenia with increased marrow megakaryocytes, bleeding, altered mentation, and seizure. Coagulation parameters were inconsistent with disseminated intravascular coagulation; a clinical diagnosis of thrombotic thrombocytopenic purpura (TTP) was made. Plasmapheresis resulted in improvement on two separate occasions. The diagnosis of tumor-associated TTP should be considered in cancer patients. Plasmapheresis may be more effective than plasma transfusion alone in this syndrome, perhaps via removal of tumor-induced immune complexes from the circulation. Aggressive management of this complication seems justified in cancer patients for whom effective chemotherapy exists.

Adenocarcinoma↗
PubMed1985

Activity of arildone with or without interferon against acute hemorrhagic conjunctivitis viruses in cell culture.

Arildone (WIN 38020; 4-[6-(2-chloro-4-methoxyphenoxy)hexyl]-3,5-heptanedione) inhibited the infectivity of acute hemorrhagic conjunctivitis viruses in tissue culture. Arildone did not inhibit interferon (IFN) production or IFN activity. Treatment of cultures with combinations of arildone and IFN resulted in an additive inhibition of acute hemorrhagic conjunctivitis virus production.

Antiviral Agents↗
PubMed1984

Prophylaxis of fever and infection in adult cancer patients. A placebo-controlled trial of oral trimethoprim-sulfamethoxazole plus erythromycin.

Oral trimethoprim-sulfamethoxazole (Bactrim) plus erythromycin (TMZ-E) was tested versus placebo (P) as prophylaxis for bacterial infection in a randomized, double-blind trial in adult cancer patients receiving cytotoxic chemotherapy expected to result in significant neutropenia. The incidence of adverse reactions attributable to TMZ and/or E was higher in drug-treated episodes (18 of 28 vs 3 of 29 for P, P less than 0.0005) resulting in poorer compliance. The incidence of fever was not significantly different between episodes treated with TMZ-E (18/27) and those treated with P (17/29), nor was there a significant difference in the median interval between the onset of neutropenia and the onset of fever. However, 14 of 18 fevers in TMZ-E recipients were without a documented infectious source compared with only 6 of 17 in P recipients (P less than 0.05). The same patterns were apparent even when episodes in which compliance with the regimen was either excellent or good were considered separately. There was no significant difference in the number of deaths from infection between TMZ-E and P recipients (3/27 vs 1/29). It is concluded that TMZ-E prophylaxis is of no practical benefit, may mask the cause of infection in febrile neutropenic cancer patients, and is associated with substantial toxicity.

Adolescent↗
PubMed1984

Doppler ultrasonic detection of particulate release during hemodialysis with cellulose hollow-fiber and sorbent suspension reciprocating dialyzers.

Doppler ultrasound is a noninvasive technique for monitoring moving objects such as flowing blood while ignoring stationary objects such as shunt tubing. A Doppler system was investigated to determine its sensitivity in detecting particulate release in blood during hemodialysis. Seven hemodialysis procedures with dogs and six trials with humans were done using a sorbent suspension reciprocating dialyzer ( SSRD ). Two additional trials were done with humans using a cellulose acetate hollow-fiber dialyzer (HFD). A large increase (approximately twofold) was found in the reflected Doppler signal in outflowing blood from the SSRD and HFD in both dogs and humans. Numerous additional studies to characterize the nature of the particulate matter showed platelet aggregates in the dogs and fibrinogen-fibrin degradation products in the humans to be present in the outflowing blood. In vitro studies suggested microscopic air bubbles (less than 25 micron in diameter) may have contributed to the particulate matter detected during hemodialysis by this sensitive monitoring system.

Animals↗
PubMed1982

Estimation of Free, Conjugated, and Diffusible Indole-3-acetic Acid in Etiolated Maize Shoots by the Indolo-alpha-pyrone Fluorescence Method.

Procedures for estimating free indoleacetic acid (IAA extracted from tissue homogenates by aqueous acetone), conjugated IAA (extracted by aqueous acetone and hydrolyzed by 1 n KOH), and diffusible IAA (diffused from the excised tissue into water), in shoots of etiolated 3-day-old maize (Zea mays L. cv. GH 390) seedlings are described, the indolo-alpha-pyrone fluorescence method being used to assay IAA. The reliability of the procedure is shown by comparative IAA determinations of the extracts using the gas chromatography-mass spectrometry method in which the methyl ester, heptafluorobutyryl derivative of IAA is assayed using the selected-ion-monitoring technique with deuterated IAA as an internal standard. A 3-millimeter-long coleoptile tip, a coleoptile with its included leaves and nodal region (whole coleoptile), and a mesocotyl each contains 0.2, 1.7, and 1.5 nanograms of free IAA, respectively. The whole coleoptile and the mesocotyl contain slightly less conjugated IAA than their content of free IAA. IAA diffuses from the coleoptile tip at the rate of 1.0 nanograms per tip per hour; from the base of the whole coleoptile and a set of leaves excised from a coleoptile, IAA diffuses at the rate of 0.62 and 0.17 nanogram per plant part per hour, respectively. The data obtained support the classical assumption that the coleoptile tip produces IAA. It is also suggested that some IAA is decomposed during its downward transport in the coleoptile.

Journal Article↗
PubMed1982

Sources of Free IAA in the Mesocotyl of Etiolated Maize Seedlings.

Sources of free indole-3-acetic acid (IAA) for the mesocotyl of intact etiolized maize ((Zea mays L.) seedlings are evaluated. The coleoptile unit, which includes the primary leaves and the coleoptilar node, is the main source of free IAA for the mesocotyl. The seed and the roots are not immediate sources of IAA supply. Dependence of the apical growing region of the mesocotyl on the coleoptile unit as a source of free IAA is almost total. One-half or more of the supply of IAA comes from the coleoptile tip, the rest mainly from the primary leaves. Removal of the coleoptile tip results in inhibition of mesocotyl elongation. The hypothesis that growth of the mesocotyl is regulated by auxin supplied by the coleoptile is supported. Conjugated forms of IAA appear to play little part in regulating the levels of free IAA in the shoot.

Journal Article↗
PubMed1980

Improved Procedure for the Estimation of Nanogram Quantities of Indole-3-acetic Acid in Plant Extracts using the Indolo-alpha-pyrone Fluorescence Method.

The indolo-alpha-pyrone fluorescence method of determining indole-3-acetic acid (IAA) is improved by adding butylated hydroxytoluene (BHT), an antioxidant, to samples: addition of BHT increases the fluorescence intensities and decreases their variability so that amounts of IAA as small as 0.1 to 1 nanogram become measurable. Interfering compounds, 4-chloroindole-3-acetic acid and 5-hydroxyindole-3-acetic acid, can be separated from IAA by thin-layer chromatography using polyamide as the solid support, and benzene-ethyl acetate-acetic acid (70:25:5, v/v) as the developing solvent. Polyamide thin-layer chromatography is also superior in purifying IAA without significant loss or decomposition.A serious problem in extracting IAA from plant tissues is the considerable loss. Losses can result from decomposition of IAA when its solutions in organic solvents are evaporated to dryness, apparently due to some impurity in the solvents. Decomposition can be eliminated by simple treatments of the solvents, i.e. addition of BHT, washing with water, and passage through cotton wool. The latter is particularly effective in the case of ethyl acetate and ether. Loss of IAA by photodecomposition is also substantial even in dried samples. Ways to minimize the conversion of indole-3-pyruvic acid to IAA during extraction procedure are also described.A revised procedure of IAA extraction and determination is proposed. Applied to etiolated shoots of maize seedlings, it enables content to be estimated (18 nanograms per gram fresh weight) with over 90% recovery in terms of [(14)C]IAA added at the beginning of the extraction.

Journal Article↗
PubMedDate not supplied

Push-pull sorbent based pheresis for treatment of acute hepatic failure: the BioLogic-detoxifier/plasma filter System.

The BioLogic-DT (detoxifier) System is an extracorporeal blood treatment device that uses the membranes of a cellulosic plate dialyzer to propel blood in and out through a single lumen access (on a 12 sec cycle) and circulates a suspension of powdered charcoal and cation exchanger through the dialysate spaces to absorb many soluble toxins in the treatment of hepatic failure. The BioLogic-DTPF (detoxifier/plasma filter) System adds two Gambro plasma filters downstream from the plate dialyzer, which allows most of the blood plasma to pass out of the blood, contact powdered charcoal in a suspension, and then return to the blood during each 12 sec cycle (creating push-pull sorbent based pheresis). A roller pump exchanges charcoal suspension between the plasma filter case and a 700 ml bag of powdered charcoal suspension. At a blood flow rate of 150-200 ml/min, 100 ml/min of plasma moves bidirectionally through the plasma filter membranes. Direct contact of plasma with charcoal outside the plasma filter membranes removes creatinine with a clearance rate equal to plasma flow (100 ml/min); clearance of strongly protein bound toxins, such as unconjugated bilirubin, is lower (10-40 ml/min). In this article, the authors explain the mechanisms of operation of this system and present in vitro tests that define its chemical efficiency. Also described are potential problems, tests that indicate the severity of these problems, and monitors and algorithms to detect or avoid these problems in clinical use of the system. The results of the treatment of two patients with acute hepatic failure and coma using the BioLogic-DTPF System are reviewed.

Aged↗
PubMedDate not supplied

Systemic inflammatory response syndrome treatment by powdered sorbent pheresis: the BioLogic-Detoxification Plasma Filtration System.

Systemic inflammatory response syndrome (SIRS) is one of the most common causes of death in intensive care unit patients. The detoxification plasma filtration (DTPF) system (HemoCleanse, Inc., West Lafayette, IN) combines the DT hemodiabsorption system in series with a push-pull pheresis PF system (a suspension of powdered sorbents surrounding 0.5 microm plasma filter membranes). Bidirectional plasma flow (at 80-100 ml/min) across the PF membranes provides direct contact between plasma proteins and powdered sorbents, as well as clearance of cytokines (tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6) at a rate of 15-25 ml/min, without evidence of saturation for 90 minutes. In a U.S. Food and Drug Administration approved study we treated eight patients with SIRS and organ failure with a single DTPF treatment, using powdered charcoal as sorbent in four patients and powdered charcoal and silica in four patients. Treatments proceeded for 6 hours with proper heparin anticoagulation (activated clotting time 250-300 sec) and appeared safe. All patients improved during the treatments and each had increased blood pressure and decreased need for pressor agents. Plasma cytokine levels stabilized or decreased during treatment and were significantly lower the morning after treatment. Multiple organ dysfunction (MOD) and Acute Physiology Chronic Health Evaluation II scores and organ function gradually improved in most patients, and two patients survived for more than 28 days and two for more than 14 days. The DTPF System may prove beneficial in treatment of patients with sepsis.

Adult↗
PubMedDate not supplied

Morphine-induced suppression of cytotoxic T lymphocyte activity in alloimmunized mice is not mediated through a naltrindole-sensitive delta opioid receptor.

The effect of chronic morphine exposure on natural killer (NK) activity in vivo and the generation of cytotoxic T lymphocytes (CTLs) in vitro and in vivo was investigated. Chronic exposure to morphine (10(-5) - 10(-11) M) in vitro had no effect on the generation of antigen-driven effector cells. However, the daily administration of morphine (50.0 mg/kg, s.c.) into alloimmunized mice (C57BL/6 into C3H/HeN) for 11 days resulted in a decrease in peritoneal and splenic CTL activity but not splenic NK activity. In addition, there was a 60% decrease in the number of thymocytes recovered from chronic morphine-treated mice compared to vehicle-treated controls. However, the overall percentage of CD4+CD8-, CD4-CD8+ and CD4+CD8+ thymocytes did not change between the two groups of treated animals. Pretreatment of the mice with the delta 1-selective antagonist, (E)-7-benzylidine-7-dihydronaltrexone (BNTX, 0.6 mg/kg, s.c.) did not block morphine-mediated suppression of splenic CTL activity but did block morphine-induced suppression of peritoneal lymphocyte CTL activity. In addition, BNTX pretreatment alone augmented splenic NK activity and such augmentation was blocked following chronic morphine exposure. In contrast, the delta-selective antagonist, naltrindole (20.0 mg/kg, s.c.), had no effect alone nor antagonized the action of morphine on CTL activity. Splenic CTL effector cells from either treated group of animals lysed their target (EL-4 lymphoma) through a Ca(2+)-dependent mechanism. Collectively, the results indicate morphine suppresses CTL activity through an indirect pathway, insensitive to naltrindole rather than through direct lymphocyte opioid receptors.

Animals↗
PubMedDate not supplied

Neurologic improvement of patients with hepatic failure and coma during sorbent suspension dialysis.

Fifteen patients with acute deterioration of liver function, high serum ammonia, and an average coma level of 3.9 (of 4) were treated for 8-12 hrs daily with a system that uses the membranes of a cellulosic plate dialyzer to pump blood through a single access at 200-225 ml/min, and includes a sorbent suspension as dialysate. Neurologic status of the patients was declining before treatment, but significantly improved during each treatment and over the course of 1-12 (average, 4) treatments. Diastolic blood pressure and pulse rate normalized. For half the patients, treatment with the BioLogic-DT system served as a bridge to liver transplant or liver recovery.

Adult↗
PubMedDate not supplied

Effect of sorbent-based dialytic therapy with the BioLogic-DT on an experimental model of hepatic failure.

An experimental model of hepatic failure in the dog has been developed in which the liver is devascularized in two stages. Under general anesthesia, a portacaval shunt is created, ligatures placed around the hepatic and gastroduodenal arteries, and the dog recovered. Two days later under general anesthesia, the ligatures are pulled, converting hepatic insufficiency to hepatic failure. Five control animals developed hypotension, severe lactic acidosis, hypoglycemia, and increasing liver enzyme levels during 6 hrs of follow-up. The BioLogic-DT system includes a cellulosic plate dialyzer with a suspension of powdered charcoal and cation exchangers as dialysate. Five animals were treated with the BioLogic-DT for 6 hrs after creation of hepatic failure. These animals were more stable physiologically, developed less lactic acidosis and less enzyme elevation, and maintained high normal blood glucose levels. The results help explain the clinical improvement demonstrated in patients with hepatic failure treated by the BioLogic-DT, and confirm that many of the toxins of hepatic failure are dialyzable and bound by simple sorbents such as charcoal and cation exchangers.

Ammonia↗